JP2000120448A - Fuel compressor system for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an energy efficiency in a fuel compressor system for a gas turbine. SOLUTION: An electric motor 21 driving a fuel compressor 11 is controlled in frequency by an inverter 22, and a command signal is output to the inverter 22 from a control device 23, thereby converts an inverter frequency into a variable frequency to be outputted to the electric motor 21 out of the inverter 22. Since the compression work of the fuel compressor can be adjusted according to a case by adjusting an inverter frequency in response to a case when an inverter frequency is to be set up, a fuel compressor system can thereby be transformed into one very high in efficiency from the stand point of energy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel compressor system for a gas turbine applied to a cogeneration system using, for example, city gas as fuel.

[0002]

2. Description of the Related Art FIG.
1 is an overall configuration diagram of a cogeneration system to which a conventional gas turbine fuel compressor system disclosed in Japanese Patent No. 5056 is applied.

In FIG. 1, a cogeneration system 200 includes a gas turbine 30, a gas turbine fuel compressor system 10 for compressing and supplying fuel to the gas turbine 30, and a power generation operation by transmitting a driving force of the gas turbine 30. And a running power generation system 40.

[0004] Fuel compressor system 10 for gas turbine
Is connected to a fuel compressor 11, a fuel suction passage 12 having one end communicating with a fuel source (not shown) and the other end communicating with an inlet 11 a of the fuel compressor 11, and one end communicating with a discharge port 11 b of the fuel compressor 11. A fuel discharge passage 13 whose other end communicates with the gas turbine 30, and a fuel suction passage 1 which bypasses the fuel compressor 11.
A bypass passage 14 connecting the fuel injection passage 2 and the fuel discharge passage 13;
External control on-off valve 1 interposed in the middle of bypass passage 14
5, a pressure control device 16 that detects the pressure in the fuel discharge flow path 13 and transmits a valve opening amount setting signal to the external control on-off valve 15 according to the detected pressure, and is provided in the fuel discharge flow path 13. The storage tank 17 is provided with a safety valve 17 a attached to the storage tank 17.

The gas turbine 30 has a turbine section 3
1 and an output shaft 32 extending from the center of the turbine section 31, and the fuel discharge passage 13 communicates with the fuel gas inlet 31 a of the turbine section 31 via the shut-off valve 18.
In addition, the turbine section 31 has an air intake 31b for sucking air from outside and an exhaust gas outlet 31c for discharging exhaust gas burned in the turbine section 31.

The power generation system 40 includes a power generator 41 connected to an output shaft 32 of the gas turbine 30 and a power transmission system 42 connected to the power generator 41 and transmitting power generated by the power generator 41. .

In the cogeneration system 200 having the above structure, the fuel gas flowing from the fuel suction passage 12 is supplied to the fuel compressor 11 at a predetermined pressure (generally 8 to 1).
The pressure is increased to 5 kg / cm ² G) and flows out to the fuel discharge channel 13. Further, the fuel gas is introduced into the turbine section 31 of the gas turbine 30 from the fuel gas inlet 31a via the storage tank 17 and the shut-off valve 18 provided in the fuel discharge channel 13. Then, the fuel gas thus introduced into the turbine section 31 is burned after being mixed with the air introduced from the air intake port 31b. This combustion causes the mixed gas to expand, and the expansion force drives the gas turbine 30. This driving force is transferred from the output shaft 32 of the gas turbine 30 to the generator 41, whereby the power generation operation is performed.

When the gas turbine 30 is stopped in an emergency, the shutoff valve 18 is closed to shut off the supply of fuel to the gas turbine 30. When the shutoff valve 18 is closed, the pressure in the fuel discharge channel 13 increases. The control device 16 detects this pressure increase, and sends an opening degree setting signal to the control on-off valve 15 according to the detected pressure. As a result, the control opening / closing valve 15 is opened at a predetermined opening, and the fuel gas in the fuel discharge passage 13 is recirculated to the fuel suction passage 12 to prevent an abnormal increase in the pressure on the fuel discharge passage 13. I have. Similarly, even when the load on the generator 41 is cut off and the gas turbine 30 is operated in the idling mode, the opening of the external control on-off valve 15 is controlled by the control device 16 to prevent the abnormal pressure rise in the fuel discharge passage 13. I do. Thus, in any case, the fuel discharge passage 1
3 is controlled so as to be constant.

[0009]

Since the conventional gas turbine fuel compressor system is configured as described above, the control of the flow rate and the pressure of the fuel gas are performed only by controlling the opening of the external control on-off valve. Depending on the operating state of the gas turbine, the fuel compressor is operated at a constant speed so as to maintain the set value of the pressure control device. That is, even when the gas turbine does not need a large amount of gas flow in the idling state or when the gas turbine is stopped in an emergency, the fuel compressor needs the same constant power as in the steady state, which is not preferable from the viewpoint of energy saving. .

[0010] Therefore, the present invention has been made in view of the above circumstances, and has as its technical object to improve energy efficiency in a fuel compressor system for a gas turbine.

[0011]

According to a first aspect of the present invention, there is provided a gas turbine fuel compressor system for compressing and supplying fuel to a gas turbine. The fuel compressor system for a gas turbine includes a fuel compressor, a fuel suction passage having one end communicating with a fuel source and the other end communicating with an inlet of the fuel compressor, and one end having a discharge port of the fuel compressor. A fuel discharge passage having the other end communicating with the gas turbine, an electric motor driving the fuel compressor, and a power supply frequency connected to an AC power supply and converted from the AC power supply to a predetermined frequency. And a control device for outputting a command signal to the power supply frequency conversion device, wherein the power supply frequency conversion device receives the command signal and outputs the power supply frequency. Is that as fuel compressor system for a gas turbine, characterized in that the variable conversion.

According to the first aspect of the present invention, there is provided a fuel compressor system for a gas turbine, wherein a fuel compressor has a fuel suction passage having one end communicating with a fuel source and the other end communicating with a suction port of the fuel compressor. A fuel discharge passage having one end communicating with the discharge port of the fuel compressor and the other end communicating with the gas turbine, an electric motor driving the fuel compressor, and being connected to and input from an AC power supply. The power supply frequency converter includes a power supply frequency converter that converts a power supply frequency to a predetermined frequency and outputs the same to a motor, and a controller that outputs a command signal to the power supply frequency converter.
The power supply frequency conversion device receives a command signal from the control device, variably converts the input power supply frequency, and outputs the converted power supply frequency to the electric motor. Therefore, when the gas turbine is in an idling state and does not require a large gas flow rate, the control device outputs a command signal to the power supply frequency conversion device to reduce the power supply frequency converted by the power supply frequency conversion device. Therefore, the power supply frequency converter receives the command signal from the control device, converts the input power supply frequency into an AC current having a smaller frequency, and outputs the AC current to the electric motor.
Thus, the motor runs at a lower frequency, thus reducing the compression work of the fuel compressor driven by the motor. For this reason, the discharge flow rate of the fuel gas in the fuel discharge passage decreases. In this way, it is possible to reduce the amount of work in the fuel compressor by flowing the minimum necessary fuel gas flow rate in the idling state. On the other hand, when it is necessary to increase the flow rate of the fuel gas to the gas turbine due to an increase in the load on the generator system side, the control device:
A command signal for increasing the power supply frequency converted by the power supply frequency converter is output to the power supply frequency converter. For this reason, the power supply frequency conversion device receives the command signal from the control device, converts the input power supply frequency into an AC current having a higher frequency, and outputs the AC current to the electric motor. Thus, the motor runs at a higher frequency, thus increasing the compression work of the fuel compressor driven by the motor. For this reason, the discharge flow rate of the fuel gas in the fuel discharge passage increases. In this way, a fuel gas flow rate satisfying the requirements of the gas turbine can be flowed. As described above, according to the present invention, the compression work of the fuel compressor can be adjusted depending on the case, so that a fuel compressor system with extremely high energy efficiency can be obtained.

Further, in solving the above technical problem, the control device transmits a drive command signal based on PID control during automatic operation of the gas turbine fuel compressor system. A fuel compressor system for a gas turbine, wherein the fuel compressor is driven and controlled so that the pressure in the fuel discharge flow path is made closer to a target set pressure by outputting to the power supply frequency converter. preferable.

According to the second aspect of the present invention, during the automatic operation of the gas turbine fuel compressor system, a drive command signal based on the PID control is output from the control device to the power supply frequency conversion device, whereby the fuel discharge flow The pressure in the path is brought closer to the target set pressure. Therefore, during the automatic operation of the fuel compressor system, even if the pressure in the fuel discharge passage is largely different from the target set pressure, the pressure in the fuel discharge passage is sharply controlled by the PID control of the power supply frequency converter. Approach the target set pressure quickly and without overshoot. Therefore, it is possible to approximate the set pressure with good response. Further, even during the steady operation, when the pressure in the fuel discharge passage increases or decreases due to the fluctuation of the load of the generator system, the pressure in the fuel discharge passage is quickly increased to the target set pressure by the PID control of the power supply frequency converter. Get closer. Therefore, a response delay after a load change can be reduced.
Therefore, a malfunction of the fuel compressor system due to an abnormal rise in pressure in the discharge flow path due to a response delay or an overshoot, or a shutdown of the fuel compressor system and the cogeneration system due to an abnormal decrease in pressure. Can be prevented.

In the PID control, the pressure is a control amount, and the power supply frequency output from the power supply frequency converter to the motor is an operation amount. In addition, the pressure as the control amount is an input value of a detected value of the pressure in the fuel discharge channel. Then, the PID is calculated from the difference between the pressure input to the control device and the target set pressure.
An operation amount is obtained by performing a calculation based on the control, and a signal related to the operation amount is output to the power supply frequency converter as a command signal.

In this case, the control device may be arranged such that, when the automatic operation of the gas turbine fuel compressor system is started, the pressure in the fuel discharge passage becomes a predetermined pressure. Until then, it is preferable to set an upper limit value for the power supply frequency output from the power supply frequency converter to the electric motor.

According to the third aspect of the present invention, when the automatic operation of the gas turbine fuel compressor system is started, the control device controls the power supply frequency conversion device until the pressure in the fuel discharge passage reaches a predetermined pressure. Since the upper limit is set for the power supply frequency output to the electric motor from the above, a sudden increase in pressure in the fuel discharge passage 13 can be suppressed more reliably in the initial stage of the automatic operation.

Further, in solving the above technical problem, the control device according to the fourth aspect of the present invention, when stopping the gas turbine fuel compressor system, stops according to various stop conditions. It is preferable that the fuel compressor be stopped and controlled by selecting a processing mode and outputting a stop command signal based on the selected stop processing mode to the power supply frequency converter.

According to the fourth aspect of the present invention, the control device selects a stop processing mode according to various stop conditions when stopping the fuel compressor system for a gas turbine.
A stop command signal is output to the power supply frequency converter based on the stop processing mode selected in this manner, and the power supply frequency converter receives the stop command signal and converts the frequency of the input AC current to a desired frequency. Output to the motor.
For this reason, it is possible to execute the optimal stop processing suitable for various stop conditions.

In general, such a system stop state (stop condition) of the fuel compressor system is stopped while giving top priority to ensuring safety, such as when a gas leak occurs or an emergency stop button is pressed. Various stop situations are supposed, for example, when the operator gives priority to system maintenance such as when the operator needs to temporarily suspend the system for his / her own convenience and then immediately start the system. The present invention assumes the stop modes corresponding to various stop situations as described above, and executes the stop processing based on each stop mode, thereby optimally stopping the fuel compressor system according to each stop state. That can be done.

In this case, it is preferable that the stop control of the fuel compressor is performed in accordance with the stop command signal, out of PID stop control, digital value stop control, and free-run stop control. The stop control is preferably performed by any one of the control methods.

According to the fifth aspect of the invention, for example, when stopping while giving the highest priority to ensuring safety, the fuel compressor is stopped in a free run. Stopping the fuel compressor immediately in this way ensures safety. When the maintenance of the system is given the highest priority, the stop of the fuel compressor is controlled by PID control or digital value control. By controlling the stop of the fuel compressor in this way, maintenance of the system is reliably ensured.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a cogeneration system to which a gas turbine fuel compressor according to the present embodiment is applied. In the figure, a cogeneration system 100 includes a gas turbine 30, a gas turbine fuel compressor unit 10 that compresses and supplies fuel to the gas turbine 30, and a power generation in which a driving force of the gas turbine 30 is transmitted to perform a power generation operation. And a unit 40.

The compressor unit 10 includes a fuel compressor 11
And one end communicates with a fuel source (not shown) and the other end
A fuel suction passage 12 communicating with the first suction port 11a, a fuel discharge passage 13 having one end communicating with the discharge port 11b of the fuel compressor 11 and the other end communicating with the gas turbine 30, and driving the fuel compressor 11; A motor 21 to be driven, an inverter 22 as a power supply frequency converter electrically connected to the AC power supply A,
A control device 23 that outputs a command signal to the inverter 22 is provided, and these are housed in an enclosure 24. Further, a discharge gas pressure sensor 25 and a discharge gas temperature sensor 26 are mounted on the fuel discharge flow path 13, and a gas leak detection sensor 27 is mounted on the inner wall portion of the enclosure 24.
Has been entered. 28 is a safety valve, 11c is a safety valve built in the fuel compressor, and 29 is a check valve.

The inverter 22 receives an AC current from an AC power supply A. The input AC power is converted into a predetermined frequency by the inverter 22, and the converted AC drive current is output to the electric motor 21.

The control device 23 receives the detection signals from the discharge gas pressure sensor 25, the discharge gas temperature sensor 26, and the gas leak detection sensor 27 as described above, and based on the input detection signals, the inverter 22 To output a command signal.

A PID operation circuit (not shown) is incorporated in the control device 23. In the PID calculation circuit, the control amount is pressure, the operation amount is the frequency of the AC power supply,
Calculation is performed using the pressure detected by the discharge gas pressure sensor 25 input to the control device 23 as the control amount (pressure), and the frequency of the AC drive current as the operation amount is returned as a command signal. Accordingly, the deviation amount in the PID control of the present embodiment is a deviation pressure between the pressure detected by the discharge gas pressure sensor 25 and the target set pressure. In order to minimize the deviation pressure optimally, the pressure (discharge gas pressure sensor A signal related to an operation amount (frequency of AC drive power) based on PID control using the pressure detected at 25 as a control amount is output to the inverter 22 as a command signal.

The gas turbine 30 has a turbine section 3
1 and an output shaft 32 extending from the center of the turbine section 31, and the fuel discharge passage 13 communicates with the fuel gas inlet 31 a of the turbine section 31 via the shield valve 18.
In addition, the turbine section 31 has an air intake 31b for sucking air from outside and an exhaust gas outlet 31c for discharging exhaust gas burned in the turbine section 31. The opening information of the shielding valve 18 is input to the control device 23. Further, although not shown, from the gas turbine 30 side, an operation command, a stop command, and the like of the gas turbine 30 are provided.
A discharge pressure command in the fuel discharge passage 13 for maintaining the rotation speed of the gas turbine 30 in accordance with the load is input to the control device. In this example, this discharge pressure command corresponds to the target set pressure.

The power generation unit 40 includes a power generator 41 connected to an output shaft 32 of the gas turbine 30 and a power transmission system 32 connected to the power generator 41 and transmitting electric power generated by the power generator 41. .

In the cogeneration system 100 having the above configuration, the fuel gas flowing from the fuel suction passage 12 is supplied to the compressor 11 at a predetermined pressure (generally 8 to 15 k).
g / cm ² G) and flows out to the fuel discharge channel 13. Further, the fuel gas is introduced into the turbine section 31 of the gas turbine 30 from the fuel gas inlet 31a via the shutoff valve 18. Then, the fuel gas thus introduced into the turbine section 31 is burned after being mixed with the air introduced from the air intake port 31b. This combustion causes the mixed gas to expand, and the expansion force drives the gas turbine 30. This driving force is transferred from the output shaft 32 of the gas turbine 30 to the generator 41, whereby the power generation operation is performed.

FIG. 2 is a control time chart for automatically operating the gas turbine fuel compressor system 10 in this embodiment. In the figure, after the power is first turned on, when the start button (not shown) or the like is pressed to start the system, the inverter power is turned on. Next, when automatic operation is selected from a touch panel (GP panel) (not shown) attached to the control device 23, the inverter 22 is operated. Next, an operation command is sent from the gas turbine 30 side to the control device 23.
Is input to After the input of the operation command, the discharge pressure command (target set pressure) input to the control device 23 monotonically increases in the initial operation stage until reaching the final target set pressure (for example, 8 kgf / cm ² ). Therefore, the target discharge pressure 13 and the fuel discharge flow path 13 detected by the discharge gas pressure sensor 25
Deviation pressure from the actual pressure in The control device 23 determines an inverter frequency by PID control based on the deviation pressure, and outputs the determined inverter frequency to the inverter 22 as a drive command signal. The inverter 22 converts the power supply frequency input from the AC power supply A into an inverter frequency as a drive command signal input from the control device 23 and outputs the frequency to the electric motor 21. Electric motor 21
Is operated in accordance with the input inverter frequency,
The fuel compressor 11 is driven. In this way, the driving of the fuel compressor 11 is PID-controlled by the control device 23. However, as shown in the figure, in the initial stage of the operation, the pressure in the discharge flow path detected by the discharge gas pressure sensor 25 is reduced to a predetermined pressure (for example, 0.5 kg / cm ² ), the inverter frequency is limited to an upper limit (for example, 7.5 Hz).
Is provided. When the pressure in the discharge passage becomes equal to or higher than the predetermined pressure, the upper limit is released, and the normal PID control is performed. By such PID control, the pressure in the fuel discharge channel 13 reaches the target set pressure quickly (within approximately one minute), and becomes a steady state.

In a steady state, when there is a load change from the generator system 40 side, the gas turbine 30
Then, the opening degree of the shielding valve 18 is adjusted in order to secure a flow rate corresponding to the changed load. Thereby, the fuel discharge passage 13
The discharge flow rate of the fuel gas in the chamber changes, and the discharge pressure also changes. Also in this case, by performing PID control for controlling the power supply frequency of the inverter 22, the pressure in the discharge flow path quickly reaches the target set pressure. Thereafter, when a stop command is input from the gas turbine 30 to the control device 23, the system stops according to a predetermined stop process.

As described above, the fuel compressor system 100 for a gas turbine according to the present embodiment controls the frequency of the electric motor 21 driving the fuel compressor 11 by the inverter 22 as described above, and
, The inverter frequency output from the inverter 22 to the electric motor 21 is variably converted. Therefore, when the discharge flow rate of the fuel gas is small, the inverter frequency can be set so as to decrease the compression work of the fuel compressor 11, and when it is desired to increase the discharge flow rate of the fuel gas, the compression work of the fuel compressor 11 is increased. The inverter frequency can be set so that As described above, since the compression work of the fuel compressor can be adjusted depending on the case, a fuel compressor system with extremely high energy efficiency can be obtained.

As described above, the control device 23 outputs a drive command signal (inverter frequency) based on PID control to the inverter 22 during the automatic operation of the gas turbine fuel compressor system 10, The drive of the fuel compressor is controlled so that the pressure in the fuel discharge flow path 13 approaches the target set pressure, so that the pressure in the fuel discharge flow path 13 is sharply increased to the target set pressure without overshoot. . Therefore, the response delay of the pressure can be reduced.

With the conventional bypass valve control system alone, even if PID control of the bypass valve opening was performed, appropriate control as in this example was impossible, but the inverter was used as described above. According to the compressor control of the PID control, optimal control as a fuel compressor can be obtained. Also,
According to the fuel compressor rotation control of the PID control using the inverter as described above, the supply gas flow rate can be quickly changed, so that the gas turbine can be optimally operated without the storage tank. Becomes

In this embodiment, when stopping the gas turbine fuel compressor system 10, four stop processing modes are selected according to various conditions. The four stop processing modes are an automatic stop first mode, an automatic stop second mode,
An abnormal stop first mode and an abnormal stop second mode. The selection of these stop processing modes will be described based on a control flowchart relating to the stop of the system shown in FIG.

First, when any stop information is input from inside or outside the system, an automatic / abnormal stop mode selection subroutine shown in step 300 is executed. In the automatic / abnormal stop mode selection subroutine, first, in step 301, the input stop information is
It is determined whether or not the stop information is based on a gas leak abnormality. If the stop information is stop information based on a gas leak abnormality, the process jumps to a subroutine (step 400) for executing the first abnormal stop mode. If it is not the stop information based on the gas leak abnormality, the process proceeds to step 302. In step 302, it is determined whether the input stop information is stop information based on the pressing of the emergency stop button. If the stop information is based on the pressing of the emergency stop button, a subroutine for executing the first abnormal stop mode (step 40) as in the case of a gas leak abnormality
Jump to 0). If it is not stop information based on the pressing of the emergency stop button, the process proceeds to step 303. In step 303, it is determined whether or not the input stop information is stop information based on an abnormality of the inverter 22. If the stop information is based on the abnormality of the inverter 22, the process jumps to a subroutine (step 500) for executing the second abnormal stop mode. If it is not the stop information based on the abnormality of the inverter 22, the process proceeds to step 304. In step 304, it is determined whether or not the input stop information is stop information based on the fact that the discharge gas pressure sensor 25 itself is abnormal. If the stop information is based on the fact that the discharge pressure sensor 25 itself is abnormal, the process jumps to a subroutine (step 500) for executing the second abnormal stop mode, similarly to the case of the inverter abnormality. If it is not the stop information based on the fact that the discharge gas pressure sensor 25 itself is abnormal, the process proceeds to step 305. In step 305, it is determined whether or not the vehicle is currently in automatic operation. If the automatic operation is currently being performed, the routine jumps to a subroutine (step 600) for executing the first automatic stop mode. If it is not currently in automatic operation, that is, if it is in manual operation, the flow jumps to a subroutine (step 700) for executing the second automatic stop mode. After returning from the above four subroutines, step 306 is executed.
Proceed to. In step 306, it is determined whether the stop has been completed. If the stop has been completed, it returns. If the stop has not been completed, the process returns to step 301.

In the case of a gas leak abnormality or an emergency stop, the stop processing is executed in the first abnormal stop mode (step 400). This abnormal stop first mode (step 40)
0) is shown in the control flowchart of FIG.

As shown in the figure, in the abnormal stop first mode, first, in step 401, the target set pressure is set to 0 kgf / cm ² . Next, step 402
In, the inverter frequency is set to 0 Hz. Next, in step 403, the inverter 22 is stopped. Next, at step 404, the inverter 22
Is turned off. Further, after the ventilation fan (not shown) is stopped in step 405 and the oil cooling fan (not shown) is stopped in step 406,
In step 407, the automatic or manual operation is terminated. In step 408, completion of the system is recognized, and the process returns.

In the abnormal stop first mode, it is necessary to give top priority to ensuring safety, for example, to prevent diffusion of fuel gas to the outside due to gas leakage and to prevent occurrence of an emergency during an emergency stop. For this reason, all controls are immediately stopped. By this stop processing, the supply of electric power to the electric motor 21 and the fuel compressor 11 is immediately cut off, so that the fuel compressor performs a free-run stop.

If the inverter 22 itself is abnormal or the discharge gas pressure sensor 25 itself is abnormal, a stop process is executed in the second abnormal stop mode (step 500). FIG. 5 shows a control flowchart in the abnormal stop second mode (step 500).

As shown in the figure, in the abnormal stop second mode, first, at step 501, the target set pressure is set to 0 kgf / cm ² . Next, step 502
In, the inverter frequency is set to 0 Hz. Next, in step 503, the inverter 22 is stopped. Next, at step 504, the inverter 22
Is turned off. Next, in step 505, the automatic or manual operation is terminated, and in step 506, the completion of the system is recognized, and the process returns.

In the abnormal stop second mode, the inverter 2
2 and the discharge gas pressure sensor 25 itself. In this case, since the input power to the electric motor 21 is immediately shut off, there is a relatively high demand for ensuring safety. Therefore, as in the abnormal stop first mode, the inverter 2
Stop 2 immediately. Therefore, the fuel compressor 11 performs a free-run stop. Further, unlike the abnormal stop first mode, the ventilation fan and the oil cooling fan are not stopped. In this stop mode, since no gas leakage has occurred, even when the ventilation fan and the oil cooling fan are operating, the fuel gas does not leak outside.

In the abnormal stop first mode and the abnormal stop second mode described above, there is a situation in which ensuring safety is given the highest priority. Therefore, the fuel compressor 11 is subjected to free-run stop control. Thereby, the fuel compressor 11 is immediately stopped, and the safety of the system is ensured. Note that, in these modes, the fuel compressor 11 stops in a free run, so strictly speaking, the stop of the fuel compressor 11 is not controlled. However, in order to comprehensively explain the purpose of the present example and the present invention, the expression "free-run stop control" is used. In this case, the control device 23 sends the inverter 2
Immediately shutting off the command signal to 2 can be rephrased as free-run stop control of the fuel compressor 11.

During normal operation, normal abnormalities other than gas leak abnormality, emergency stop, abnormality of the discharge gas pressure sensor 25 itself, abnormality of the inverter itself (for example, abnormality of discharge gas temperature, abnormality of cooling oil temperature, abnormality of ventilation fan) , Suction gas pressure abnormality, oil pressure abnormality, etc.), when information on the end of automatic operation by the operator is input to the control device, when a stop command is input by control of the gas turbine 30 side, etc. , Automatic stop first mode (step 600)
The stop process is executed by the command. FIG. 6 is a flowchart in the first automatic stop mode (step 600).

As shown in the figure, in the first automatic stop mode, first, in step 601, it is determined whether or not the pressure in the fuel discharge passage 13 detected by the discharge gas pressure sensor 25 is stored as a set pressure. . If not stored, in step 602, the pressure in the fuel discharge channel 13 at that time is stored as the set pressure, and then the process proceeds to step 603. If it is stored, the process directly proceeds to step 603. In step 603, a deceleration timer (a two-second timer in this example) starts. Next, at step 604, it is determined whether or not the deceleration timer has expired (time-up).
If the deceleration timer has expired, the routine proceeds to step 605, where a predetermined pressure (0.2 in this example) is calculated from the stored set pressure.
The value obtained by subtracting 5 kg / cm ² ) is updated as a new set pressure, and the process proceeds to step 606. If the deceleration timer has not expired, the process proceeds directly from step 604 to step 606.
Proceed to. Here, the automatic stop first mode is repeatedly executed at every CPU clock cycle (in this example, 20 mmsec.), So that by repeatedly executing steps 603, 604 and 605, the set pressure becomes the predetermined pressure every 2 seconds. (In this example, it decreases stepwise by 0.25 kg / cm ² ).

In step 606, PID control is performed using the set pressure. That is, the inverter frequency is calculated by PID control so as to optimally reduce the deviation between the set pressure and the pressure detected by the discharge pressure sensor 25, and the inverter frequency thus calculated is controlled as a stop command signal. Output from the device 23 to the inverter 22. The inverter 22 converts the power supply frequency input from the AC power supply into an inverter frequency as a stop command signal input from the control device 23 and outputs the frequency to the electric motor 21. The PID stop control of the electric motor 21 is performed in accordance with the input inverter frequency.

After calculating the inverter frequency at step 606 and outputting a predetermined command, the process proceeds to step 607. In step 607, it is determined whether the inverter frequency calculated in step 606 is 0 Hz or less. If the calculated inverter frequency is higher than 0 Hz, the process returns. If the calculated inverter frequency is higher than 0 Hz, the process returns. If the calculated inverter frequency is equal to or lower than 0 Hz, the process proceeds to step 608.
In step 608, it is determined whether or not the pressure in the fuel discharge passage 13 detected by the discharge gas pressure sensor 25 is sufficiently low to stop the system (in this example, 4 kg / cm ² or less). You. The pressure in the fuel discharge passage 13 is
Not reduced enough to shut down the system (4 kg /
cm ² or more) is returned. Fuel discharge passage 13
If the internal pressure is sufficiently low, step 609 is executed.
Proceed to. In step 609, it is recognized that the system has completed the stop. Then, in step 610, it is determined whether or not a stop command has been input from the gas turbine to the control device 23. If the stop command has not been input, the process returns (in this case, the first automatic stop mode is continued, and if the operation command is input again, the process is restarted).
If a stop command has been input, the process proceeds to step 611. In step 611, the automatic operation is terminated, and thereafter, after the inverter is stopped in step 612, the process returns.

In the first mode of the automatic stop described above, there is no possibility of falling into a situation where security is given priority, and this is a stop state in which maintenance of the system is given priority. In this case, the PID stop control of the fuel compressor 11 is performed as described above. When the fuel compressor is stopped in a free-run mode, the fuel compressor may break down depending on the energization state immediately before the stop. On the other hand, if the stop control of the fuel compressor 11 is quickly performed by the PID control, the fuel compressor 11 does not fail due to the control at the time of the stop, and the maintenance of the system is reliably ensured. .

During a manual operation, when a normal abnormality other than a gas leak abnormality, an emergency stop, an abnormality of the discharge gas pressure sensor 25 itself, or an abnormality of the inverter itself occurs, or information on the end of the manual operation by the operator is controlled. When input to the device,
The stop processing is executed in the second automatic stop mode (step 700). FIG. 7 is a flowchart in the automatic stop second mode (step 700).

As shown in the figure, in the automatic stop second mode, first, at step 701, a process of decreasing the inverter frequency is executed. In this reduction processing, the variable frequency band of the inverter of 0 to 60 Hz is made to correspond to digital values represented by a plurality of predetermined values (0 to 4000 in this example) at equal intervals, and the current inverter frequency is set to this value. The digital value is converted to a digital value, a digital value obtained by subtracting one digital from the current digital value is updated as a new digital value, and the frequency obtained by converting the new digital value to the inverter frequency again is updated as a new inverter frequency.
Set the inverter frequency. Accordingly, the inverter frequency is reduced by 60/4000 Hz every clock cycle of the CPU. In this example, the above stop control is called digital value stop control. Next, step 702
It is determined whether or not the new set inverter frequency is equal to or lower than 0 Hz. New set inverter frequency is 0
If the frequency is higher than Hz, the process returns. If the new set inverter frequency is 0 Hz or less, step 7
Go to 03. In step 703, it is recognized that the stop of the system has been completed. Next, the manual operation is terminated in step 704, the inverter is stopped in step 705, and the routine returns.

The automatic stop second mode described above is basically selected when the system is operated by manual operation. In such a case, the PID control is executed to optimize the fuel discharge pressure. There is no need to plan for For this reason, in this mode, the digital value stop control of the fuel compressor 11 is performed. The digital value stop control is a forced stop control that does not perform the feedback control unlike the PID stop control. Further, since the fuel compressor 11 is not suddenly stopped unlike the stop of the free run, the maintenance of the fuel compressor 11 can be performed.

As described above, the control device 23 in the gas turbine fuel compressor system 100 according to the present embodiment sets various stop conditions (safety is the highest priority) when the gas turbine fuel compressor system 100 is stopped. Stop processing modes (abnormal stop 1st mode, abnormal stop 2nd mode, automatic stop 1st mode, automatic stop 2nd mode) according to the stop condition that is in the situation and the stop condition that places priority on system maintenance The fuel compressor 11 is controlled to stop by selecting and outputting a stop command signal based on the selected stop processing mode to the inverter (free-run stop control, PID
Stop control, digital value stop control)
The fuel compressor system can be optimally stopped according to each stop state.

[0055]

As described above, according to the present invention,
In the event of an emergency stop of the compressor, an emergency stop of the gas turbine, and a load fluctuation or start-up idling of the gas turbine, the fuel compressor can be quickly brought into an optimal state, thereby reducing power consumption. Thus, a fuel compressor system with good energy efficiency can be obtained. Also,
Since a storage tank is not required, a compact, lightweight and inexpensive system can be provided, and a fuel gas is not released to the atmosphere. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a cogeneration system to which a fuel compressor system for a gas turbine is applied in an embodiment of the present invention.

FIG. 2 is a time chart when the fuel compressor for a gas turbine is automatically operated in the embodiment of the present invention.

FIG. 3 is a flowchart of a stop mode selection subroutine in the embodiment of the present invention.

FIG. 4 is a flowchart of a subroutine for executing an abnormal stop first mode in the embodiment of the present invention.

FIG. 5 is a flowchart of a subroutine for executing an abnormal stop second mode in the embodiment of the present invention.

FIG. 6 is a flowchart of a subroutine for executing an automatic stop first mode according to the embodiment of the present invention.

FIG. 7 is a flowchart of a subroutine for executing a second automatic stop mode in the embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a cogeneration system to which a fuel compressor for a gas turbine is applied in a conventional technique.

[Explanation of symbols]

Reference Signs List 10 ... Gas turbine fuel compressor system 11 ... Fuel compressor 11a ... Suction port 11
b ... Discharge port 12 ... Fuel suction flow path 13 ... Fuel discharge flow path 18 ... Shutoff valve 21 ... Electric motor 22 ... Inverter (power frequency conversion device) 23 ... Control device 24 Enclosure 25 Discharge pressure sensor 26 Discharge temperature sensor 30 Gas turbine

Claims (5)

[Claims] 1. A gas turbine fuel compressor system for compressing and supplying fuel to a gas turbine, the gas turbine fuel compressor system comprising: a fuel compressor; one end communicating with a fuel source; A fuel suction passage communicating with a suction port of the fuel compressor, a fuel discharge passage having one end communicating with a discharge port of the fuel compressor and the other end communicating with the gas turbine, and driving the fuel compressor. A power supply frequency converter connected to an AC power supply, converting a power supply frequency input from the AC power supply to a predetermined frequency and outputting the predetermined frequency to the motor, and outputting a command signal to the power supply frequency converter. A fuel compressor system for a gas turbine, comprising a control device, wherein the power supply frequency conversion device receives the command signal and variably converts the power supply frequency. 2. The fuel discharge device according to claim 1, wherein the control device outputs a drive command signal based on PID control to the power supply frequency conversion device during automatic operation of the gas turbine fuel compressor system. A fuel compressor system for a gas turbine, wherein the fuel compressor is drive-controlled so that the pressure in the flow path approaches a target set pressure. 3. The power supply frequency conversion device according to claim 2, wherein the control device is configured to control the power supply frequency conversion until the pressure in the fuel discharge passage reaches a predetermined pressure when starting the automatic operation of the gas turbine fuel compressor system. A fuel compressor system for a gas turbine, wherein an upper limit value is set for a power supply frequency output from the device to the electric motor. 4. The control device according to claim 1, wherein the control device selects a stop processing mode according to various stop conditions when stopping the gas turbine fuel compressor system, and based on the selected stop processing mode. A fuel compressor system for a gas turbine, wherein the fuel compressor is controlled to stop by outputting a stop command signal to the power supply frequency converter. 5. The stop control of the fuel compressor according to claim 4, wherein the stop control of the fuel compressor is performed by any one of PID stop control, digital value stop control, and free-run stop control in accordance with the stop command signal. A fuel compressor system for a gas turbine, which is controlled to be stopped.